WO2012020769A1 - Method for producing nickel-containing complex compound - Google Patents

Abstract

Provided is a low-cost production method for precursor for use in production of a cathode active material for a lithium-ion rechargeable battery that can be used in a wide voltage range, has a high discharge capacity and a high safety, and is excellent in charge-discharge cycle durability. The method includes: step (1) of obtaining a slurry suspension containing particles of nickel-M element-containing complex compound by decomposing nickel ammine complex by heating a nickel-M element-containing solution or dispersion that contains a nickel ammine complex and M element source (with the proviso that M is at least one kind selected from the group consisting of a transition metal element excluding Ni and Co, an alkaline-earth metal element, and aluminum); and step (2) of obtaining a granulated substance of the nickel-M element-containing complex compound by drying and granulating the slurry suspension.

Description

Method for producing nickel-containing composite compound

The present invention relates to a method for producing a nickel-M element-containing composite compound suitable for a positive electrode active material precursor of a lithium ion secondary battery, and a positive electrode material for a lithium ion secondary battery using the produced nickel-M element-containing composite compound It relates to the manufacturing method.

In recent years, as devices become more portable and cordless, demands for non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries that are small, lightweight, and have high energy density are increasing. Examples of the positive electrode active material for the non-aqueous electrolyte secondary battery include LiCoO ₂ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNiO ₂ , LiNi _0.8 Co _0.2 O ₂ , LiMn _2. A composite oxide containing lithium and a transition metal element such as O ₄ and LiMnO ₂ is known.

Among them, lithium-nickel-cobalt-manganese-containing composite oxides are advantageous in terms of cost because they contain inexpensive manganese, and have a good balance of safety and battery characteristics. It is expected as a positive electrode material.

However, the lithium-nickel-cobalt-manganese-containing composite oxide obtained by using the conventional solid-phase method in which the powders of the respective metal sources are mixed and fired cannot provide good battery characteristics. It has been proposed to use nickel-cobalt-manganese coprecipitated hydroxide synthesized using a salt as a raw material (see Patent Documents 1 to 3).
It has also been proposed to synthesize a lithium-nickel-cobalt-containing composite oxide by thermally decomposing a nickel-cobalt ammine complex (see Patent Document 4).
Furthermore, a method is proposed in which a slurry in which a compound containing a plurality of elements such as nickel, cobalt and manganese is dispersed is spray-dried using a spray dryer or the like to form a granulated body (Patent Documents 5 to 10). reference)

Japanese Patent Laid-Open No. 2002-201028 JP 2003-059490 A JP 2000-149923 A Japanese Patent Application Laid-Open No. 2001-077628 JP 2005-123180 A JP 2005-251717 A JP 2003-034536 A JP 2003-034538 A JP 2003-051308 A Japanese Patent Laid-Open No. 2005-141983

When synthesizing a lithium-nickel-cobalt-manganese-containing composite oxide, as described in Patent Document 1 and Patent Document 2, sodium hydroxide is used for an aqueous solution of sulfate or the like in which nickel, cobalt, manganese, and the like are dissolved. In general, a coprecipitation method in which an aqueous solution in which an alkali such as ammonium sulfate is dissolved and an aqueous solution in which ammonium sulfate or the like is dissolved is dropped while adjusting pH to crystallize a coprecipitated hydroxide.

Patent Document 3 describes that a small amount of different elements such as boron is added to a nickel-cobalt-manganese positive electrode material to improve battery characteristics. In general, it is preferable that such different elements are uniformly distributed in the positive electrode material. However, when the coprecipitation method described in Patent Document 3 is used, the applicable element species and chemical species are not limited. For example, in the case of an element such as Mg, it is difficult to coprecipitate. Even when alkali can be added to coprecipitate elements, it affects the crystallization conditions, makes it difficult to synthesize dense particles, and the cathode material contains a large amount of impurities such as sodium ions and sulfate ions. There are problems such as.

In the method of thermally decomposing cobalt nickel ammine complex described in Patent Document 4, high pressure steam is blown into a solution containing nickel ammine complex and cobalt ammine complex to synthesize cobalt nickel salt. In order to further improve battery performance, synthesis of composite compounds containing other elements in addition to nickel and cobalt is desired, but ammine complex salts composed of other elements are much more unstable than cobalt nickel ammine complex salts. The synthesis of complex compounds containing other elements has not been known so far.

In Patent Documents 5 to 10, a slurry in which a nickel compound, a cobalt compound, and a manganese compound are dispersed is pulverized with a bead mill or the like, and then spray-dried with a spray dryer or the like to produce granulated particles. In this case, since a slurry in which various raw materials are dispersed is pulverized with a bead mill or the like, impurities derived from the dispersion media are mixed, and battery characteristics such as discharge capacity and charge / discharge cycle durability tend to deteriorate. Further, when the particle size of the solid material is reduced by pulverization, the viscosity of the slurry is remarkably increased, so that the solid content concentration of the slurry needs to be lowered. When the solid concentration decreases, the amount of water evaporated by spray drying increases, the production cost increases, the particle size of the granulated product obtained by spray drying decreases, and it is difficult to obtain a dense granulated product. Become. In particular, as in Patent Document 8, a slurry in which a lithium compound, a nickel compound, and a manganese compound are dispersed is pulverized, and an average particle size of 0.5 μm or less is spray-dried to produce granulated particles. In this case, it is necessary to make the particles finer to 0.5 μm or less, and much time and energy are required for pulverization, resulting in a significant cost increase. Moreover, it becomes necessary to lower the solid content concentration of the slurry, and it becomes very difficult to obtain a dense granulated body.

The present invention can solve such problems, has a uniform composition, low impurity content, can be used in a wide voltage range, has a high discharge capacity, high safety, high fillability, charge / discharge An inexpensive method for producing a nickel-containing composite compound suitable for producing a positive electrode active material for lithium ion secondary batteries having excellent cycle durability, and production of a positive electrode active material for lithium ion secondary batteries using the produced nickel-containing composite compound The purpose is to provide a method.

As a result of intensive research, the present inventors have found that the above-described problems can be satisfactorily achieved by an invention having the following summary.
(1) Nickel-M containing nickel ammine complex and M element source (wherein M element is at least one selected from the group consisting of transition metal elements other than Ni and Co, alkaline earth metal elements and aluminum) Step 1 of obtaining a suspension slurry containing particles of a nickel-M element-containing composite compound by heating the element-containing solution or dispersion to decompose the nickel ammine complex, and drying and granulating the suspension slurry A method for producing a nickel-M element-containing composite compound for a secondary battery positive electrode active material, comprising the step 2 of obtaining a granulated product of an M element-containing composite compound.
(2) In the nickel -M element-containing complex compound, Ni, the ratio of Co and M _element, when the Ni a _Co b _{M c,} in atomic ratio, 0.1 ≦ a ≦ 0.85,0 ≦ b ≦ The method for producing a nickel-M element-containing composite compound according to (1), wherein 0.85, 0.03 ≦ c ≦ 0.8, and a + b + c = 1.
(3) The nickel-M element-containing composite compound according to (1) or (2), wherein the nickel-M element-containing composite compound is a compound containing at least one selected from the group consisting of a hydroxyl group, a carbonate group, and an OOH group. A method for producing a composite compound.
(4) In the step 1, the nickel-M element-containing solution or dispersion is heated at 80 to 250 ° C. under a pressure of 0.03 to 2 MPa. Manufacturing method of M element containing complex compound.
(5) In any one of the above (1) to (3), the step 1 introduces and heats steam at 100 to 250 ° C. under a pressure of 0.03 to 2 MPa to the nickel-M element-containing solution or dispersion. A method for producing a nickel-M element-containing composite compound according to claim 1.

(6) The method for producing a nickel-M element-containing composite compound according to any one of (1) to (5) above, wherein the nickel ammine complex is a carbonate ammine complex.
(7) The method for producing a nickel-M element-containing composite compound according to any one of the above (1) to (6), wherein the M element source contains manganese and the manganese source is a manganese ammine complex.
(8) The method for producing a nickel-M element-containing composite compound as described in (7) above, wherein the manganese ammine complex is manganese carbamate.
(9) Nickel-M according to any one of the above (1) to (8), wherein the dry granulation in the step 2 is performed by spray-drying a nickel-M element-containing solution or dispersion. A method for producing an element-containing composite compound.
(10) The method for producing a nickel-M element-containing composite compound according to any one of the above (1) to (9), wherein the suspended slurry has a solid content concentration of 10% by mass or more and a viscosity of 2 to 1000 mPa · s. .
(11) The production of the nickel-M element-containing composite compound according to any one of the above (1) to (10), wherein the nickel-M element-containing composite compound obtained in step 2 has an average particle diameter D ₅₀ of 6-30 μm. Method.
(12) The method for producing a nickel-M element-containing composite compound as described in any one of (1) to (11) above, wherein the sodium content is 0.01% by mass or less.
(13) The method for producing a nickel-M element-containing composite compound according to any one of (1) to (12), wherein the sulfur content is 0.1% by mass or less.
(14) Lithium baked at 700 to 1100 ° C. in an oxygen-containing atmosphere after mixing the nickel-M element-containing composite compound obtained by the production method according to any one of (1) to (13) above and a lithium compound -Method for producing nickel-M element-containing composite oxide.
(15) A lithium ion secondary battery comprising a positive electrode, a negative electrode, a nonaqueous electrolyte, and an electrolytic solution, wherein the positive electrode uses a positive electrode active material for a lithium ion secondary battery obtained by the production method described in (14) above Production method.

According to the present invention, a lithium ion secondary battery having a uniform composition, low impurity content, usable in a wide voltage range, high discharge capacity, high safety, and excellent charge / discharge cycle durability. The positive electrode active material and its precursor are provided at low cost. *

It is not necessarily clear why the nickel-cobalt-M element-containing composite compound provided by the present invention exhibits excellent characteristics as a positive electrode active material precursor for lithium ion secondary batteries as described above. It can be considered as follows.

In the conventional coprecipitation method using metal sulfate as a raw material, it is included in sulfate ions (SO ₄ ²⁻ ), chloride ions (Cl ⁻ ), and alkalis used for neutralization in the production process. Sodium ions (Na ⁺ ) are difficult to wash, and these ions remain as impurities in the positive electrode material. Due to the influence of these residual impurities, it is considered that in the battery using the produced positive electrode material, the discharge capacity is reduced or the movement of lithium ions during charging / discharging is hindered and the discharge rate characteristics are deteriorated. . In particular, impurities such as sodium ions are the same alkali metal as lithium, and are taken into the crystal of the positive electrode material to cause distortion in the crystal structure, which is considered to deteriorate the charge / discharge cycle durability.

On the other hand, in the method of the present invention using the thermal decomposition of nickel ammine complex, ammonia and carbon dioxide other than the raw material element components are released out of the system, so that no impurities remain in the positive electrode material, and the above impurities Therefore, in a battery using the produced positive electrode material, it is considered that characteristics such as discharge capacity, discharge rate characteristics, and charge / discharge cycle durability do not deteriorate. Further, in the method of the present invention, by thermally decomposing the ammine complex, the particles in which the elements are uniformly dispersed are precipitated, and the slurry in which the particles are dispersed is dried and granulated, so that each element in the positive electrode material It is considered that the battery characteristics such as discharge capacity, discharge rate characteristics, and charge / discharge cycle durability can be further improved in the battery using this positive electrode material.

Furthermore, in the method of the present invention, the particle diameter and the particle shape can be controlled within a desired range by granulating a suspension slurry in which the particles of the nickel-M element-containing composite compound are uniformly dispersed. Can be improved.

2 is a SEM image of the nickel-cobalt-manganese composite compound obtained in Example 1.

In the present invention, the ammine complex refers to a complex having an amine including ammonia as a ligand, and when an organic amine is used as a ligand as an amine, the ammine complex is also referred to as an ammine complex. Specifically, the ligand of the ammine complex is preferably at least one selected from the group consisting of ammonia (NH ₃ ), an aliphatic derivative of ammonia, diamine, pyridine, aniline, dipyridyl, and phenanthroline. Among these, at least one member selected from the group consisting of ammonia (NH ₃ ), triethanolamine, pyridine, aniline, dipyridyl and phenanthroline is more preferable, and ammonia (NH ₃ ) is particularly preferable. As ligands, coordination other than ammine complexes such as aqua (OH ₂ ), carbonato (CO ₃ ²⁻ ), cyano (CN ⁻ ), oxalato (C ₂ O ₄ ²⁻ ), hydroxo (OH ⁻ ), etc. May contain children. The number of coordinated ammonia should just contain at least one, and may be two or more.

As the amine source used for forming the ammine complex, liquid ammonia, aqueous ammonia, ammonium carbonate, or ammonium bicarbonate is used. Furthermore, one kind selected from the group consisting of aliphatic derivatives of ammonia, diamine, pyridine, aniline, dipyridyl, and phenanthroline is preferred, and in view of cost, an ammine complex with ammonia is more preferred. In addition, the ligand other than ammonia of the ammine complex is preferably an carbonate carbonate complex containing carbonato (CO ₃ ²⁻ ), and the counter ion is preferably a carbonate ion. The carbonate source or carbonate ion source is not particularly limited, but carbon dioxide is particularly preferable. The above-mentioned ammonium carbonate is a compound whose form is represented by the chemical formula (NH ₄ ) ₂ CO ₃ , but usually available reagents include ammonium hydrogen carbonate (NH ₄ .HCO ₃ ) and ammonium carbamate (NH ₂ COONH ₄ ). Since this ammonium carbamate forms a stable ammine complex with Mn, when M element contains Mn, it is preferable to use ammonium carbamate as an amine source. That is, when the M element contains manganese, the raw material of manganese is not particularly limited, but among these, it is preferable to use an manganese ammine complex, and more preferable to use manganese carbamate.

In the present invention, the raw material of the nickel ammine complex is not particularly limited, and among these, metals, hydroxides, carbonates, oxyhydroxides, or oxides are preferable, and metals, hydroxides, carbonates, or oxyhydroxides are preferred. More preferred. Specifically, the nickel source is preferably metallic nickel, nickel oxide, nickel hydroxide, nickel carbonate, basic nickel carbonate, or nickel oxyhydroxide.

A nickel ammine complex-containing aqueous solution can be synthesized by adding these nickel sources to ammonia water in which ammonium carbonate or the like is dissolved and stirring at 20 to 60 ° C., preferably for 30 minutes to 12 hours.

In the present invention, the M element is at least one element selected from the group consisting of transition metal elements other than Co and Ni, alkaline earth metal elements, and aluminum. Here, the transition metal element represents a transition metal element of Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12 of the Periodic Table. Among these, the M element is preferably at least one selected from the group consisting of Mn, Al, Mg, Zr, Ti, and Hf. Further, from the viewpoint of discharge capacity, safety, charge / discharge cycle durability, etc., the M element is more preferably at least one element selected from the group consisting of Mn, Al and Mg, and Mn is particularly preferable. .

In the present invention, the nickel-M element-containing solution or dispersion heated in Step 1 does not necessarily need to dissolve all components, and some of the components may be dispersed in the solution. Including solutions in colloidal form. Further, the nickel-M element-containing solution or dispersion may be an organic solvent or water, and is not particularly limited, but an aqueous solution in which the ammine complex and the raw material are highly soluble is preferable.

When the M element contained in the nickel-M element-containing solution or dispersion is an M-element ammine complex, all the elements contained in the nickel-M element-containing solution are dissolved. Impurities such as Fe that are difficult to form an ammine complex can be removed. In particular, when M element is Mn, since it often contains a large amount of Fe impurities that adversely affect battery characteristics, it is preferable since a nickel-M element-containing composite compound with much less impurities than before can be obtained.

In the present invention, the M element source is preferably in the form of a solution. When the M element source is a solution, a mixed solution of nickel ammine complex is heated and thermally decomposed to obtain a so-called coprecipitation composite compound in which nickel and element M are uniformly dispersed in the particles at the atomic level. The solvent of the mixed solution is preferably water.

When the M element source is solid, the chemical species is not particularly limited, but metal, hydroxide, carbonate, oxyhydroxide, or oxide is preferable, and hydroxide, carbonate, oxyhydroxide is preferable. Or an oxide is more preferable. The average particle diameter _{D 50} of the M element source is preferably 10μm or less, more preferably 8 [mu] m, more preferably 5μm or less. When D ₅₀ exceeds 10 μm, the M element in the particles obtained after heating tends to be non-uniform. The smaller the D _50, the more uniform the composition can be obtained. However, the smaller the D _{50, the} higher the production cost. Therefore, considering the balance with the battery characteristics, the average particle size D ₅₀ of the M element compound is preferably 0.01 μm or more. .1 μm or more is more preferable, and 0.5 μm or more is more preferable.

Note that the average particle size D ₅₀ in the present invention, determine the particle size distribution on a volume basis, the cumulative curve the total volume was 100%, volume-reduced cumulative cumulative curve is the particle size of the point at which 50% 50 It means% diameter _{(D 50).} In the present invention, it may be simply referred to as _{D 50. Further,} the _{D 10} of the volume-reduced cumulative 10% diameter _means a volume-reduced cumulative 90% diameter and the _{D 90.} The particle size distribution is obtained from a frequency distribution and a cumulative volume distribution curve measured with a laser scattering particle size distribution measuring apparatus. The particle size is measured by sufficiently dispersing the particles in an aqueous medium by ultrasonic treatment or the like and measuring the particle size distribution (for example, using Microtrac HRA (X-100) manufactured by Nikkiso Co., Ltd.). Further, the average particle diameter D _50, if the particles to be measured is a secondary particle, it is the volume average particle diameter of the secondary particle diameter of primary particles formed by agglomerating one another, when the particles consisting only of primary particles Is the average particle size for the primary particles.

The nickel ammine complex and the nickel ammine complex contained in the nickel-M element-containing solution or dispersion containing the M element source have a nickel element concentration (mass%) of preferably 1 to 12%, more preferably 3 to 8%. The concentration of the M element source is preferably 1 to 12%, more preferably 3 to 8%, as the M element concentration (% by mass). The molar ratio of nickel and M element in the nickel-M element-containing solution or dispersion is preferably equal to the molar ratio of nickel and M element in the target nickel-M element-containing composite compound.

In order to improve the charge / discharge cycle durability and large current charge / discharge performance of the lithium ion secondary battery, the nickel-M element-containing solution or dispersion preferably further contains a Co source. The Co source is not particularly limited, but a Co ammine complex capable of forming a solution is preferable. In such a case, the cobalt ammine complex contained in the nickel-M element-containing solution or dispersion has a cobalt element concentration (mass%) of preferably 1 to 12%, more preferably 3 to 8%. The Co ammine complex can be synthesized by the same method as the above nickel ammine complex. When the nickel-M element-containing solution or dispersion contains a Co source, the molar ratio of nickel-cobalt-M element in the solution or dispersion is nickel-cobalt in the target nickel-cobalt-M element-containing composite compound. It is preferably equal to the molar ratio of the -M element.

The method for heating the nickel-M element-containing solution or dispersion is not particularly limited, but it is preferably 80 to 250 ° C, more preferably 80 to 180 ° C, and more preferably 100 to 180 ° C. As a heating method, it is preferable to use 100 ° C. or higher steam. By heating, the ammine complex forms a nickel-M atom-containing composite compound and ammonia or amine, but when ammonia or amine stays in the reaction system, the composite compound forms an ammine complex again and dissolves. Therefore, in order to advance the thermal decomposition reaction efficiently, it is important to distill off the produced ammonia or amine out of the reaction system. By introducing steam at 100 ° C. or higher, ammonia or amine is distilled out of the reaction system together with excess steam, and the thermal decomposition reaction of the ammine complex can be promoted. The temperature of the steam to be introduced is preferably 100 to 250 ° C, more preferably 120 to 180 ° C. A method in which the nickel-M element-containing solution or dispersion is directly heated may be used, but more preferably, the nickel-M element-containing solution or dispersion is sequentially added to the heated water boiled by heating or steam introduction. It is preferred to decompose the complex. By carrying out thermal decomposition by sequential addition, ammonia or amine can be efficiently distilled out of the reaction system, and the thermal decomposition reaction can proceed stably. The pressure in the reaction vessel may be under reduced pressure or high pressure, preferably 0.03 to 2 MPa, more preferably 0.2 to 1 MPa. The heating time is preferably 0.1 to 12 hours, more preferably 0.5 to 10 hours, and particularly preferably 1 to 6 hours.

In the present invention, a pulverization step of pulverizing the composite particles dispersed in the suspension slurry obtained in step 1 may be included. As a grinding method, wet ball mill grinding, wet bead mill grinding, wet vibration mill grinding, or the like can be applied.

In the present invention, the suspension slurry obtained in step 1 is preferably concentrated as necessary and used for spray drying in step 2. The solid content concentration of the slurry is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 30% by mass or more. The solid content concentration is preferably 80% by mass or less, and more preferably 50% by mass or less. When the solid content concentration is within this range, the size of the droplets to be sprayed can be easily adjusted, the particle size of the granulated particles can be easily adjusted, and no voids are formed inside the particles. In addition, the filling property of the granulated particles is further improved without sparse or dense bias. A higher solid content concentration is preferable because productivity and production efficiency are high, and since water in the slurry is small, energy required for spray drying is also reduced.

In the present invention, the solid content concentration is determined as follows. First, a part of the suspended slurry is taken and the mass of the taken slurry is measured, and then the taken slurry is dried at 100 ° C. to measure the weight of the dry powder. The solid content concentration can be obtained by dividing the mass of the measured dry powder by the mass of the collected slurry.
In this invention, you may put the grinding | pulverization process which grind | pulverizes the composite particle disperse | distributed to the suspension slurry obtained at the process 1. FIG. It is preferable to use any one of a wet ball mill, a wet bead mill, and a wet vibration mill for the pulverization. In particular, when spray-drying in the granulation step in Step 2, in order to obtain a highly spherical and dense precursor granulated particle suitable for the positive electrode material, the composite particles in the slurry are 0.5 μm or more and 3 μm or less. More preferably, the average particle diameter is adjusted to 0.7 μm or more and 2 μm or less. Grinding to less than 0.5 μm is not preferable because it takes time for grinding and increases costs, and the amount of impurities derived from the grinding / dispersion media increases. Further, the viscosity of the slurry increases, making it impossible to achieve both a viscosity suitable for spray drying and a solid content concentration. Since the nickel-M element-containing composite compound obtained in step 1 is already particles with high uniformity of element distribution, a single-phase positive electrode material that exhibits good battery characteristics even when the average particle size is 0.5 μm or more is obtained. Can do. By adjusting the average particle size of the composite particles in the slurry to the preferred average particle size shown above, a low-viscosity and high-concentration composite particle slurry for preparing highly granulated particles with high sphericity is prepared. can do.

In the present invention, a binder component can be added to the suspension slurry used for spray drying, and the binder component is preferably at least one selected from the group consisting of polyvinyl alcohol, carboxymethylcellulose, polyvinylpyrrolidone, and ammonium polyacrylate. .

The viscosity of the suspension slurry used for spray drying is preferably 2 to 1000 mPa · s, more preferably 2 to 800 mPa · s, and further preferably 2 to 500 mPa · s, and within this range, 4 to 500 mPa · s. It is preferably 4 to 300 mPa · s, more preferably 6 to 300 mPa · s, and particularly preferably 6 to 100 mPa · s. When the viscosity of the suspension slurry is in the above range, it is preferable because a spherical and uniform granulated body can be easily obtained.

In the present invention, the viscosity of the suspended slurry is generally measured by a rotary viscometer or a vibration viscometer, but may vary depending on the type of viscometer and measurement conditions. In the present invention, a LV type digital rotational viscometer DV-II + manufactured by Brookfield Co., Ltd. was measured using a small amount sample unit under the conditions of 25 ° C. and 30 rpm. When the viscosity was 100 mPa · s or less, the spindle No. 18 is used, and in the case of 100 mPa · s or more, the spindle No. 31 is 1000 mPa · s or higher, the spindle no. It is preferable to measure using 34.

In the present invention, examples of the dry granulation method include spray drying, flash drying, a method using a belt dryer, a method using a Laedige mixer, and a method using a thermoprocessor and a paddle dryer as a twin screw dryer. . Among these, the spray drying method using a spray dryer or the like is preferable because of high productivity.

When spray drying is used as the method of dry granulation, the particle size of the granulated product composed of secondary particles after granulation is determined by the solid content concentration and viscosity of the slurry, spray type, pressurized gas supply rate, It can be controlled by selecting the slurry supply speed, drying temperature and the like. In the present invention, the particle size of the precursor composed of secondary particles after dry granulation is substantially reflected in the particle size of the lithium-nickel-M element-containing composite oxide used for the positive electrode material.

In the present invention, the average particle diameter D ₅₀ of the granulated product obtained after dry granulation is preferably 5 to 25 μm. If D ₅₀ is less than 5 [mu] m, results press density of the lithium-containing composite oxide is decreased, the volume packing density of the positive electrode decreases the volume capacity density of the battery becomes low is not preferable. Further, when D ₅₀ is at 25μm greater, it may become difficult to obtain a smooth surface of the positive electrode. Particularly preferred D ₅₀ of the granulated product is 7 to 20 μm.

Nickel -M element-containing complex compound obtained by the present invention, Ni, the ratio of Co and the M _element, Ni a _Co b case of a _{M c, 0.1 ≦ a ≦ 0.85,0} ≦ b in atomic ratio It is preferable that ≦ 0.85, 0.03 ≦ c ≦ 0.8, and a + b + c = 1 because the battery characteristics are well balanced. Furthermore, 0.1 ≦ a ≦ 0.62, 0 ≦ b ≦ 0.35 and 0.03 ≦ c ≦ 0.8 are more preferable, and further 0.15 ≦ a ≦ 0.6 and 0 ≦ b ≦. 0.35 and 0.2 ≦ c ≦ 0.75 are preferable. Within the above range, the amount of expensive cobalt can be reduced and inexpensive nickel can be increased, and a nickel-M element-containing composite compound can be obtained at low cost. Further, when the lithium-nickel-M element-containing composite oxide obtained by reacting with a lithium compound is used as the positive electrode active material, it is preferable because the ratio of M element is large, so that the safety is high and the discharge capacity is high. .

In the firing step for obtaining the lithium-nickel-M element-containing composite oxide, provisional firing may be necessary, but if the proportion of Ni is 60% or less, that is, a is 0.6 or less, provisional firing is unnecessary. In order to synthesize efficiently, it is preferable that 0.25 ≦ a ≦ 0.6, 0 ≦ b ≦ 0.35, and 0.2 ≦ c ≦ 0.75. As a specific composition, for example, Ni is 0.5, Co is 0.2, and Mn is 0.3, or Ni is 0.6, Co is 0.2, and Mn is 0.2. Is preferred.

On the other hand, when safety is emphasized, it is preferable that the content of the M element is large, 0.1 ≦ a ≦ 0.3, 0.05 ≦ b ≦ 0.2, 0.5 ≦ c ≦ 0.8. Is preferred. As a specific composition, for example, a composition in which Ni is 1/6, Co is 1/6, and Mn is 4/6 is preferable.
Furthermore, when expensive cobalt is not used and only Ni and Mn are included, it is preferable that 0.2 ≦ a ≦ 0.7, b = 0, 0.3 ≦ c ≦ 0.8, More preferably, ≦ a ≦ 0.55, b = 0, and 0.45 ≦ c ≦ 0.8.
In the present invention, the amount of elements contained in the particles can be analyzed with an ICP analysis (high frequency inductively coupled plasma emission spectroscopy) apparatus.

The nickel-M element-containing composite compound obtained in the present invention is not particularly limited, but preferably contains at least one selected from the group consisting of a hydroxyl group, a carbonate group and an OOH group because of high reactivity and uniformity. Among these, the composite oxide is more preferably a compound containing both a hydroxyl group and a carbonate group.

The composition of the nickel-M element-containing composite compound obtained in the present invention is preferably represented by the following formula (1).

_{Ni a M c C p O q} H r Formula (1)

However, 0.1 ≦ a ≦ 0.85, 0.15 ≦ c ≦ 0.9, 0 ≦ p ≦ 1.6, 0.9 ≦ q ≦ 3.1, 0 ≦ r ≦ 3.1, a + c = 1. Of these, a and c are preferably 0.2 ≦ a ≦ 0.85 and 0.15 ≦ c ≦ 0.8, respectively, more preferably 0.25 ≦ a ≦ 0.8 and 0.2 ≦ c ≦ 0.75. preferable.
In _{particular, Ni a M c C p O} q H r _{is, Ni a M c (CO 3} ) x (OH) y or _preferably a Ni _a M c OOH. Here, 0 ≦ x ≦ 1, 0 ≦ y ≦ 2, and 1 ≦ x + y, and x and y may be a combination that is not an integer.

The composition of the nickel-M element-containing composite compound obtained in the present invention is more preferably represented by the following formula (2).

_{Ni a Co b M c C p} O q H r Formula (2)

However, 0.1 ≦ a ≦ 0.85, 0 ≦ b ≦ 0.85, 0.03 ≦ c ≦ 0.8, 0 ≦ p ≦ 1.6, 0.9 ≦ q ≦ 3.1, 0 ≦ r ≦ 3.1 and a + b + c = 1. Among them, a, b and c are preferably 0.1 ≦ a ≦ 0.62, 0 ≦ b ≦ 0.35, 0.03 ≦ c ≦ 0.8, 0.2 ≦ a ≦ 0.6, 0 .05 ≦ b ≦ 0.35 and 0.2 ≦ c ≦ 0.75 are more preferable. When a, b and c are in the above ranges, it is preferable because the amount of expensive cobalt can be reduced and inexpensive nickel can be increased, and a nickel-cobalt-M element-containing composite compound can be obtained at low cost.

_{Ni a Co b M c C p} O q H r _{is, Ni a Co b M c (} CO 3) x (OH) y or _preferably a Ni _a Co _b M c OOH. Here, 0 ≦ x ≦ 1, 0 ≦ y ≦ 2, and 1 ≦ x + y, and x and y may be a combination that is not an integer.

In _{Ni a Co b M c (CO} 3) x (OH) y, embodiments where Ni, Co, average valence of Mn is 2, is a combination of x and y satisfying x × 2 + y = 2 . There are some combinations of x and y that are not integers. If it is an integer, x = 1 and y = 0, or x = 0 and y = 2. The aspect in which the average valence of Ni, Co, and Mn is 3 is a combination of x and y that satisfies x × 2 + y = 3. Some combinations of x and y are not integers. As specific examples, x = 1 and y = 1, or x = 0.5 and y = 2. The granulated body of the nickel-M element-containing composite compound obtained in the present invention is preferably substantially spherical.

It is preferable that the amount of impurities contained in the nickel-M element-containing composite compound obtained in the present invention is small. Examples of impurity elements that affect battery performance include sodium (Na), sulfur (S), iron (Fe), and zirconium (Zr). The sodium content is preferably 0.01% by mass or less, and more preferably 0.005% by mass or less. The content of sodium may be 0.0001% by mass or more. The sulfur content is preferably 0.1% by mass or less, and more preferably 0.05% by mass or less. Moreover, 0.0001 mass% or more may be sufficient as content of sulfur. The iron content is preferably 0.002% by mass or less, and more preferably 0.001% by mass or less. Moreover, 0.0001 mass% or more of iron content may be sufficient. The zirconium content is preferably 0.015% by mass or less, and more preferably 0.010% by mass or less. Further, the content of zirconium may be 0.00001% by mass or more. The amount of these impurities can be measured by ICP analysis.

The particle size of the lithium-nickel-M element-containing composite oxide produced by firing the mixture of the nickel-M element-containing composite compound and the lithium compound obtained in the present invention is the same as that of the nickel-M element-containing composite compound. There is a tendency to be affected by the diameter. For this reason, when used as a positive electrode active material, the balance between safety and discharge rate characteristics is improved, so that the average particle diameter D ₅₀ of the nickel-M element-containing composite compound is preferably in the range of 6 to 30 μm. The range of 8 to 25 μm is more preferable, and the range of 10 to 20 μm is more preferable.

A nickel-M element-containing composite compound and a lithium compound are mixed and then fired to obtain a lithium-nickel-M element-containing composite oxide useful as a positive electrode material for a lithium ion secondary battery. Although the lithium compound to be used is not particularly limited, lithium hydroxide or lithium carbonate is preferable because it is inexpensive, and lithium carbonate is more preferable. Firing is preferably performed in an oxygen-containing atmosphere. Further, firing at 700 to 1100 ° C. is preferable. When the firing temperature is lower than 700 ° C., the formation of the lithium-nickel-M element-containing composite oxide is insufficient and results in containing impurity crystals. On the other hand, when the firing temperature exceeds 1100 ° C., the charge / discharge cycle durability and the discharge capacity tend to decrease. Especially, as for a calcination temperature, it is preferable that a minimum is 850 degreeC and an upper limit is 1050 degreeC. The oxygen-containing atmosphere is preferably in the air, and more specifically, the oxygen content contained in the atmosphere is more preferably 10 to 40% by volume. The firing time is preferably 1 to 24 hours, more preferably 2 to 18 hours, and particularly preferably 4 to 14 hours.

The average particle diameter D ₅₀ of the lithium-nickel-M element-containing composite oxide of the present invention is preferably 2 to 25 μm, more preferably 5 to 15 μm, and even more preferably 8 to 12 μm. The specific surface area is preferably from 0.1 to 1.0 m ² / g, more preferably from 0.2 to 0.6 m ² / g. In the present invention, the specific surface area means a value measured using the BET method. The press density is preferably 2.8 g / cm ³ or more, and more preferably 2.9 g / cm ³ or more. The upper limit is not particularly limited, but 3.6 g / cm ³ is preferable. In the present invention, the press density lithium - and the apparent density of the powder when pressed at a pressure of powder 1.0 t / cm ² of nickel -M element-containing composite oxide.

In the present invention, the amount of free alkali in the lithium-nickel-M element-containing composite oxide was determined by dispersing 5 g of the lithium-nickel-M element-containing composite oxide powder in 50 g of pure water and stirring for 30 minutes. Thereafter, the filtrate obtained by filtration is subjected to potentiometric titration with a 0.02 mol% / liter hydrochloric acid aqueous solution, and is determined from the amount of the hydrochloric acid aqueous solution used until the pH reaches 4.0.

When producing a positive electrode for a lithium secondary battery using the lithium-nickel-M element-containing composite oxide of the present invention, a carbon-based conductive material such as acetylene black, graphite, or ketjen black is used as the composite oxide powder. It is formed by mixing a material and a binder. For the binder, polyvinylidene fluoride, polytetrafluoroethylene, polyamide, carboxymethyl cellulose, acrylic resin, or the like is preferably used. The lithium-nickel-M element-containing composite oxide powder, conductive material and binder of the present invention are made into a slurry or a kneaded product using a solvent or a dispersion medium. This is supported on a positive electrode current collector such as an aluminum foil or a stainless steel foil by coating or the like to produce a positive electrode for a lithium secondary battery of the present invention.

In the lithium secondary battery using the lithium-nickel-M element-containing composite oxide of the present invention as the positive electrode active material, a porous polyethylene film, a porous polypropylene film, or the like is used as the separator. Various solvents can be used as the solvent for the electrolyte solution of the battery, and among them, carbonate ester is preferable. The carbonate ester can be either cyclic or chain. Examples of the cyclic carbonate include propylene carbonate and ethylene carbonate (EC). Examples of the chain carbonate include dimethyl carbonate, diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate, methyl isopropyl carbonate, and the like.

In the lithium secondary battery of the present invention, the carbonate ester can be used alone or in admixture of two or more. Moreover, you may mix and use with another solvent. Further, depending on the material of the negative electrode active material, the combined use of a chain carbonate ester and a cyclic carbonate ester may improve the discharge capacity, cycle characteristics, and charge / discharge efficiency.

Further, in the lithium secondary battery using the lithium-nickel-M element-containing composite oxide of the present invention as the positive electrode active material, a vinylidene fluoride-hexafluoropropylene copolymer (for example, trade name Kyner manufactured by Atchem Co.) or a fluorine A gel polymer electrolyte containing a vinylidene fluoride-perfluoropropyl vinyl ether copolymer may be used. Solutes added to the electrolyte solvent or polymer electrolyte include ClO ⁴⁻ , CF ₃ SO ³⁻ , BF ⁴⁻ , PF ⁶⁻ , AsF ⁶⁻ , SbF ⁶⁻ , CF ₃ CO ²⁻ , (CF ₃ Any one or more of lithium salts having SO ₂ ) ₂ N ^— or the like as an anion is preferably used. It is preferable to add at a concentration of 0.2 to 2.0 mol / L with respect to the electrolyte solvent or polymer electrolyte comprising the lithium salt. If it deviates from this range, the ionic conductivity is lowered and the electrical conductivity of the electrolyte is lowered. Of these, 0.5 to 1.5 mol / L is particularly preferable.

In the lithium secondary battery using the lithium-nickel-M element-containing composite oxide of the present invention as the positive electrode active material, a material capable of inserting and extracting lithium ions is used as the negative electrode active material. The material for forming the negative electrode active material is not particularly limited. For example, an oxide, a carbon compound, a silicon carbide compound, or a silicon oxide compound mainly composed of lithium metal, lithium alloy, carbon material, periodic table 14 or group 15 metal. , Titanium sulfide, boron carbide compounds and the like. As the carbon material, those obtained by pyrolyzing an organic substance under various pyrolysis conditions, artificial graphite, natural graphite, soil graphite, expanded graphite, flake graphite, and the like can be used. As the oxide, a compound mainly composed of tin oxide can be used. As the negative electrode current collector, a copper foil, a nickel foil, or the like is used. Such a negative electrode is preferably produced by kneading the active material with an organic solvent to form a slurry, and applying the slurry to a metal foil current collector, drying, and pressing.

The shape of the lithium secondary battery using the lithium-nickel-M element-containing composite oxide of the present invention as the positive electrode active material is not particularly limited. A sheet shape, a film shape, a folded shape, a wound-type bottomed cylindrical shape, a button shape, or the like is selected depending on the application.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
[Example 1] Example: To 335 g of 26 mass% aqueous ammonium carbonate solution, 245 g of 28 mass% ammonia aqueous solution and 40 g of cobalt hydroxide were added and dissolved by stirring at room temperature, and then insoluble components were removed by pressure filtration. An aqueous solution of a cobalt carbonate ammine complex was obtained. Next, after adding 220 g of 28 mass% aqueous ammonia solution and 57 g of basic nickel carbonate to 300 g of 26 mass% ammonium carbonate aqueous solution and stirring and dissolving at room temperature, the insoluble components were removed by pressure filtration to obtain nickel carbonate. An aqueous solution of an ammine complex was obtained. Furthermore, after 47 g of ammonium carbonate was added to and dissolved in 450 g of 28 mass% ammonia aqueous solution, 24 g of metal manganese powder was added and dissolved while stirring at 25 ° C., and then insoluble components were removed by pressure filtration. Thus, an aqueous solution of manganese carbamate was obtained.

An autoclave equipped with a stirrer was charged with 1 L of ion-exchanged water, 0.3 MPa steam was introduced while stirring at a constant speed, the internal pressure was 0.2 MPa, and the internal temperature was 120 ° C. To this, the aqueous solution of cobalt carbonate ammine complex, the aqueous solution of nickel carbonate ammine complex and the aqueous solution of manganese carbamate obtained above were mixed so that the molar ratio of nickel / cobalt / manganese was 5/2/3. 1 kg of the aqueous solution was added at a rate of 3 g / min. Since gas was generated simultaneously with the addition of these aqueous solutions and the internal pressure increased, the gas was released and the internal pressure was maintained at 0.2 MPa. The released gases were ammonia and carbon dioxide, and these gases were absorbed in water and recovered. Further, the contents were intermittently withdrawn from the reactor while adding the mixed solution and introducing steam. The reaction time at this time was 1.5 hours. The extracted content was a slurry in which the solid content was dispersed. After completion of the addition of the mixed solution, cooling is performed, and the remaining slurry in the reactor and the slurry extracted during the reaction are allowed to stand together, the solid content is settled, the supernatant is extracted, and the solid content concentration is 30% by mass. A suspension slurry was obtained. The obtained slurry was measured with a laser diffraction particle size distribution meter (Microtrac HRA X-100 manufactured by Nikkiso Co., Ltd.). The average particle diameter D ₅₀ of the particles dispersed in the slurry was 2.3 μm, and the viscosity of the slurry Was 9 mPa · s.

Next, 250 g of the slurry was dried while granulating using a spray dryer to obtain nickel-cobalt-manganese element-containing composite compound particles. In addition, Yamato Kagaku Co., Ltd. [GB22] was used for the spray dryer. Dry granulation was performed under the conditions of a slurry supply rate of 5 g / min, a spray gas pressure of 0.15 MPa, and a dry gas temperature of 200 ° C. to obtain granulated particles of a nickel-cobalt-manganese containing composite compound. The average particle diameter D ₅₀ is 11.2 μm, and the composition calculation of the nickel-cobalt-manganese composite compound particles based on the composition analysis and the identification result by powder X-ray diffraction shows that Ni _0.5 Co _{0. 2} Mn _0.3 (CO ₃ ) (OH) _0.16 . The total content of nickel, cobalt and manganese contained in this composite compound was 47.9% by mass. The results of quantifying the amount of impurities in the obtained granulated particles are summarized in Table 1.

A scanning electron micrograph (SEM image) of the obtained nickel-cobalt-manganese-containing composite compound granule is shown in FIG. The obtained granulated body was substantially spherical.
By mixing 30.0 g of the obtained nickel-cobalt-manganese-containing composite compound and 9.53 g of lithium carbonate having a lithium content of 18.7% by mass, firing at 960 ° C. for 14 hours in an air atmosphere, and then grinding the mixture. , represented by _{Li 1.015 [Ni 0.5 Co 0.2 Mn} 0.3] 0.985 O 2, Li substantially spherical - nickel - cobalt - to obtain a powder of manganese-containing composite oxide.
D ₅₀ of the obtained composite oxide was 9.8 μm, D ₁₀ was 5.4 μm, D ₉₀ was 18.0 μm, and the specific surface area was 0.42 m ² / g. The press density of this powder was 2.92 g / cm ³ and the amount of free alkali was 0.9 mol%.

The obtained lithium-nickel-cobalt-manganese-containing composite oxide, acetylene black, and polyvinylidene fluoride powder were mixed at a mass ratio of 90/5/5, and N-methylpyrrolidone was added to prepare a slurry. One-side coating was performed on a 20 μm thick aluminum foil using a doctor blade, dried, and roll press rolling was performed twice to produce a positive electrode sheet for a lithium battery.

The positive electrode sheet is punched out as a positive electrode, a metal lithium foil having a thickness of 500 μm is used as a negative electrode, a nickel foil of 20 μm is used as a negative electrode current collector, and a porous polypropylene having a thickness of 25 μm is used as a separator. Further, the electrolytic solution used is a LiPF ₆ / EC + DEC (1: 1) solution having a concentration of 1 M (meaning a mixed solution of EC and DEC having a mass ratio (1: 1) of LiPF ₆ as a solute. Solvents described later). Were also used to assemble two stainless steel simple sealed cell type lithium batteries in an argon glove box.

The one battery is charged at a load current of 75 mA per gram of the positive electrode active material at 25 ° C. to 4.3 V, discharged to 2.5 V at a load current of 75 mA per gram of the positive electrode active material, and The charge / discharge capacity density (sometimes referred to as initial weight capacity density in the present specification) was determined. Next, the battery was charged to 4.3 V with a load current of 75 mA, and the discharge capacity when discharged to 2.5 V with a load current of 113 mA was determined. Moreover, about this battery, the discharge capacity at the time of performing a charging / discharging cycle test 30 times continuously was calculated | required. As a result, the initial weight capacity density of the positive electrode active material at 25 ° C. and 2.5 to 4.3 V was 166.6 mAh / g. Moreover, the high load capacity maintenance factor calculated | required from the discharge capacity when discharging with a high load of 113 mA related to the discharge rate characteristic was 92.1%. The capacity retention rate after 30 charge / discharge cycles was 94.2%.

[Example 2] Example 28% by weight ammonia aqueous solution 3.0Kg was added to 26% by weight ammonium carbonate aqueous solution 5.58Kg, cobalt hydroxide 245g and basic nickel carbonate 870g were added, and stirred at room temperature to dissolve. The remaining insoluble components were removed by filtration to obtain an aqueous solution of nickel-cobalt ammine carbonate complex. On the other hand, after adding 600 g of ammonium carbonate to 4.5 kg of 28 mass% ammonia aqueous solution and dissolving it, 215 g of metal manganese powder was gradually added and dissolved while stirring at 25 ° C., and then the slightly insoluble component remained. Was removed by filtration to obtain an aqueous solution of manganese carbamate.

A 10 L autoclave equipped with a stirrer was charged with 5 L of ion exchange water, 0.3 MPa steam was introduced while stirring at a constant speed, the internal pressure was 0.2 MPa, and the internal temperature was 120 ° C. To this was added an aqueous solution of the nickel-cobalt ammine carbonate complex obtained above at a rate of 27 g / min and an aqueous solution of manganese carbamate at a rate of 15 g / min. Since gas was generated simultaneously with the addition of these aqueous solutions and the internal pressure increased, the gas was released to maintain the internal pressure at 0.2 MPa. The released gases were ammonia and carbon dioxide, and these gases were absorbed in water and recovered. Further, the contents were intermittently withdrawn from the reactor while the addition of the aqueous solution and the steam were continuously introduced. The reaction time at this time was 1.5 hours. The extracted content was a slurry in which the solid content was dispersed. After the addition of the aqueous solution of nickel-cobalt ammine carbonate complex and the aqueous solution of manganese carbamate was completed, the introduction of steam was continued for 30 minutes so that the internal pressure was maintained at 0.2 MPa. After stopping the introduction of steam, the reactor is cooled, and the remaining slurry in the reactor and the slurry extracted during the reaction are allowed to stand together, the solid content is settled, the supernatant is extracted, and the solid content concentration is 40 A suspension slurry of mass% was obtained. When the obtained slurry was measured with a laser diffraction particle size distribution meter (Microtrack HRA X-100, manufactured by Nikkiso Co., Ltd.), the average particle diameter D ₅₀ of the particles dispersed in the slurry was 5.8 μm.

The obtained suspension slurry with a solid content concentration of 40% by mass was pulverized using a circulating bead mill until the average particle size of the solid content in the slurry became 1.0 μm. In addition, Shinmaru Enterprises Co., Ltd. [Dyno mill MULTI LAB type] was used for the circulation type bead mill, and 0.3 mmφ zirconia beads were used for the grinding media. The slurry after wet pulverization had a viscosity of 860 mPa · s and a solid content concentration of 38% by mass.

Next, the slurry was dried while granulating using a spray dryer to obtain nickel-cobalt-manganese element-containing composite compound particles. In addition, Ogawara Kako Co., Ltd. [Twin Jetter NL-5 type] was used for the spray dryer. Dry granulation was carried out under the conditions of a slurry supply rate of 100 g / min, a spray gas pressure of 0.10 MPa, and a dry gas temperature of 250 ° C. to obtain granulated particles of a nickel-cobalt-manganese containing composite compound. The average particle diameter D ₅₀ is 16.1 μm, and the composition calculation of the nickel-cobalt-manganese composite compound particles based on the composition analysis and the identification result by powder X-ray diffraction shows that Ni _0.5 Co _{0. 2} Mn _0.3 (CO ₃ ) (OH) _0.3 . The total content of nickel, cobalt and manganese contained in this composite compound was 46.9% by mass. The results of quantifying the amount of impurities in the obtained granulated particles are summarized in Table 1.

By mixing 100 g of the obtained nickel-cobalt-manganese-containing composite compound and 31.1 g of lithium carbonate having a lithium content of 18.7% by mass, firing in an atmosphere at 960 ° C. for 14 hours, and then pulverizing, Li _1.015 represented by _{[Ni 0.5 Co 0.2 Mn 0.3]} 0.985 O 2, Li substantially spherical - nickel - cobalt - to obtain a powder of manganese-containing composite oxide.

D ₅₀ of the obtained composite oxide was 14.6 μm, D ₁₀ was 7.3 μm, D ₉₀ was 26.5 μm, and the specific surface area was 0.40 m ² / g. The press density of this powder was 3.12 g / cm ³ , and the amount of free alkali was 0.6 mol%.

For the obtained composite oxide powder, an electrode and a battery were prepared and evaluated in the same manner as in Example 1. As a result, the initial weight capacity density of the positive electrode active material at 25 ° C. and 2.5 to 4.3 V was 169.8 mAh / g. In addition, the high load capacity retention rate obtained from the discharge capacity when discharged at a high load of 113 mA related to the discharge rate characteristics was 94.6%. The capacity retention rate after 30 charge / discharge cycles was 96.6%.

[Example 3] Example 28% by weight ammonia aqueous solution 3.0kg was added to 26% by weight ammonium carbonate aqueous solution 5.58kg, and cobalt hydroxide 245g and basic nickel carbonate 870g were added and dissolved by stirring at room temperature. The remaining insoluble component was removed by filtration to obtain an aqueous solution of nickel-cobalt ammine carbonate complex. On the other hand, after adding 500 g of manganese carbonate to 2.0 kg of ion-exchanged water, stirring was performed to prepare a slurry. Using a circulating bead mill, this slurry was pulverized until the average particle size of the solid content in the slurry became 0.8 μm. The solid content concentration of the obtained manganese carbonate slurry was 17.2% by mass. 2615 g of this manganese carbonate slurry was slowly added to the previously prepared aqueous solution of nickel-cobalt ammonium carbonate complex with stirring to prepare a nickel-cobalt-manganese suspension.

5 L of ion-exchanged water was charged into a 20 L glass reactor equipped with a stirrer, and heated with a mantle heater until the internal temperature reached 100 ° C. While stirring, the nickel-cobalt-manganese suspension was continuously added at a rate of 10 g / min. The generated steam did not circulate but distilled off. After completion of dropping the suspension, heating and distillation were continued for 30 minutes. After stopping the heating and cooling the reactor, the stirring was stopped, the solid content was settled, the supernatant was extracted, and a suspension slurry having a solid content concentration of 30% by mass was obtained. The obtained slurry was measured by a laser diffraction particle size analyzer, the average particle diameter D ₅₀ of the particles dispersed in the slurry is 1.8 .mu.m, the viscosity of the slurry was 350 mPa · s.

Next, the slurry was dried while being granulated in the same manner as in Example 2 with a spray dryer to obtain nickel-cobalt-manganese element-containing composite compound particles. The average particle diameter D ₅₀ is 11.6 μm, and the composition calculation of the nickel-cobalt-manganese composite compound particles based on the composition analysis and the identification result by powder X-ray diffraction shows that Ni _0.5 Co _{0. 2} Mn _0.3 (CO ₃ ) (OH) _0.4 . The total content of nickel, cobalt and manganese contained in this composite compound was 46.2% by mass. The results of quantifying the amount of impurities in the obtained granulated particles are summarized in Table 1.

By mixing 100 g of the obtained nickel-cobalt-manganese-containing composite compound and 30.7 g of lithium carbonate having a lithium content of 18.7% by mass, firing in an atmosphere at 960 ° C. for 14 hours, and then grinding the mixture, Li _1.05 [Ni _0.5 Co _0.2 Mn _0.3 ] _0.985 O _{2 A} substantially spherical lithium-nickel-cobalt-manganese-containing composite oxide powder was obtained.

D ₅₀ of the obtained composite oxide was 11.4 μm, D ₁₀ was 5.8 μm, D ₉₀ was 22.8 μm, and the specific surface area was 0.54 m ² / g. The press density of this powder was 3.08 g / cm ³ and the amount of free alkali was 0.6 mol%.

For the obtained composite oxide powder, an electrode and a battery were prepared and evaluated in the same manner as in Example 1. As a result, the initial weight capacity density of the positive electrode active material at 25 ° C. and 2.5 to 4.3 V was 170.2 mAh / g. Moreover, the high load capacity maintenance factor calculated | required from the discharge capacity when discharging with a high load of 113 mA related to the discharge rate characteristic was 93.8%. The capacity retention rate after 30 charge / discharge cycles was 97.2%.

[Example 4] Comparative Example An aqueous sulfate solution containing 0.75 mol / L nickel sulfate, 0.3 mol / L cobalt sulfate and 0.45 mol / L manganese sulfate was prepared and filtered, and nickel-cobalt- A manganese-containing sulfate aqueous solution was obtained. Next, 500 g of ion-exchanged water was added to the reaction vessel, and the mixture was stirred at 400 rpm while being kept at 50 ° C. while bubbling with nitrogen gas. While supplying the nickel-cobalt-manganese-containing sulfate aqueous solution at a rate of 1.2 L / hr and the ammonia aqueous solution at a rate of 0.03 L / hr simultaneously to the ion-exchanged water, 18 mol / L sodium hydroxide was continuously supplied. The aqueous solution was supplied so that the pH in the reaction vessel was maintained at 11. The amount of liquid in the reaction system is adjusted by suction filtration through a filter, and after aging at 50 ° C. for 24 hours, the coprecipitated slurry is filtered, washed with water, and then dried at 70 ° C. to form a composite containing nickel-cobalt-manganese A compound was obtained. The average particle diameter D ₅₀ is 12.7 μm. The composition calculation of the nickel-cobalt-manganese composite compound particles based on the composition analysis and the identification result by powder X-ray diffraction revealed that Ni _0.5 Co _{0. 2} Mn _0.3 O _0.3 (OH) _1.8 . The total content of nickel, cobalt and manganese contained in this composite compound was 61.7% by mass. The results of quantifying the amount of impurities in the obtained composite compound are summarized in Table 1.

By mixing 100.0 g of the obtained nickel-cobalt-manganese-containing composite compound and 40.9 g of lithium carbonate having a lithium content of 18.7% by mass, firing at 960 ° C. for 14 hours in an air atmosphere, and then pulverizing. Li _1.015 [Ni _0.5 Co _0.2 Mn _0.3 ] _0.985 O ₂ , a substantially spherical lithium-nickel-cobalt-manganese-containing composite oxide powder was obtained.

The resulting _{D 50} of the composite oxide is _{11.6, D 10} is 7.3 _{.mu.m, D 90} is 18 [mu] m, a specific surface area of 0.36 m ² / g. The press density of this powder was 2.95 g / cm ³ , and the amount of free alkali was 0.8 mol%.

About the obtained complex oxide powder, when the battery characteristics were measured in the same manner as in Example 1, the initial weight capacity density was 165.8 mAh / g. Moreover, the high load capacity maintenance factor calculated | required from the discharge capacity when discharging with a high load of 113 mA related to the discharge rate characteristic was 91.5%. The capacity retention rate after 30 charge / discharge cycles was 93.5%. *

[Example 5] Comparative Example 200.0 g of nickel oxide (NiO) having a nickel content of 78.2 mass%, 100.8 g of cobalt hydroxide having a cobalt content of 62.3 mass%, and a manganese content of 71.5 mass% The manganese oxide (Mn ₃ O ₄ ) 122.8 g was mixed with water and stirred to obtain 1400 g slurry. Next, each raw material particle dispersed in the slurry was wet-pulverized using a circulating medium agitation type wet bead mill until the average particle diameter D ₅₀ became 0.5 μm. The slurry after wet pulverization had a viscosity of 1200 mPa · s and a solid content concentration of 30% by mass.

Subsequently, 500 g of the slurry was dried using the spray dryer in the same manner as in Example 1 to obtain nickel-cobalt-manganese element-containing composite compound particles. The average particle diameter D ₅₀ is 12.5 μm. The composition calculation of the nickel-cobalt-manganese composite compound particles based on the composition analysis and the identification result by powder X-ray diffraction shows that Ni _0.5 Co _0. It was _{2 Mn 0.3 O 0.9 (OH)} 0.51. The total content of nickel, cobalt and manganese contained in this composite compound was 71.4% by mass. The results of quantifying the amount of impurities in the obtained granulated particles are summarized in Table 1.

By mixing 50.0 g of the obtained nickel-cobalt-manganese-containing composite compound and 23.7 g of lithium carbonate having a lithium content of 18.7% by mass, firing in an air atmosphere at 960 ° C. for 14 hours, and then grinding the mixture. Li _1.015 [Ni _0.5 Co _0.2 Mn _0.3 ] _0.985 O ₂ , a substantially spherical lithium-nickel-cobalt-manganese-containing composite oxide powder was obtained.
D ₅₀ of the obtained composite oxide was 10.9 μm, D ₁₀ was 6.0 μm, D ₉₀ was 19 μm, and the specific surface area was 0.46 m ² / g. The press density of this powder was 2.89 g / cm ³ , and the amount of free alkali was 1.0 mol%.
With respect to the obtained composite oxide powder, when the battery characteristics were measured in the same manner as in Example 1, the initial weight capacity density was 161.8 mAh / g. In addition, the high load capacity retention rate obtained from the discharge capacity when discharged at a high load of 113 mA related to the discharge rate characteristics was 89.9%. The capacity retention rate after 30 charge / discharge cycles was 92.6%.

[Example 6] Comparative Example 800 g of nickel oxide (NiO) having a nickel content of 78.2 mass%, 403 g of cobalt hydroxide having a cobalt content of 62.3 mass%, manganese oxide having a manganese content of 71.5 mass% ( Ion exchange water was added to 491 g of (Mn ₃ O ₄ ) and stirred to give 5650 g of slurry. Then, by using a circulating bead mill, each raw material particles dispersed in the slurry, until the average particle diameter D ₅₀ is 1.0 .mu.m, and wet grinding. The slurry after the wet pulverization had a viscosity of 730 mPa · s and a solid content concentration of 30% by mass.

Next, the slurry was dried using a spray dryer in the same manner as in Example 2 using Okawara Kako Co., Ltd. [Twin Jetter NL-5 type], and granulated to obtain composite compound particles containing nickel-cobalt-manganese elements. Obtained. The average particle diameter D ₅₀ is 15.2 μm. The composition calculation of the nickel-cobalt-manganese composite compound particles based on the composition analysis and the identification result by powder X-ray diffraction shows that Ni _0.5 Co _{0. 2} Mn _0.3 O _0.9 (OH) _0.5 . The total content of nickel, cobalt and manganese contained in this composite compound was 71.4% by mass. The results of quantifying the amount of impurities in the obtained composite compound are summarized in Table 1.

By mixing 100 g of the obtained nickel-cobalt-manganese-containing composite compound and 47.4 g of lithium carbonate having a lithium content of 18.7% by mass, firing in an atmosphere at 960 ° C. for 14 hours, and then grinding the mixture, Li _1.05 [Ni _0.5 Co _0.2 Mn _0.3 ] _0.985 O _{2 A} substantially spherical lithium-nickel-cobalt-manganese-containing composite oxide powder was obtained.

D ₅₀ of the obtained composite oxide was 14.0 μm, D ₁₀ was 6.9 μm, D ₉₀ was 26.0 μm, and the specific surface area was 0.38 m ² / g. The press density of this powder was 2.95 g / cm ³ , and the amount of free alkali was 1.0 mol%.

For the obtained composite oxide powder, when the battery characteristics were measured in the same manner as in Example 1, the initial weight capacity density was 150.3 mAh / g. In addition, the high load capacity retention rate obtained from the discharge capacity when discharged at a high load of 113 mA related to the discharge rate characteristics was 91.8%. The capacity retention rate after 30 charge / discharge cycles was 92.1%.

According to the present invention, a lithium ion secondary battery having a uniform composition, low impurity content, usable in a wide voltage range, high discharge capacity, high safety, and excellent charge / discharge cycle durability. The positive electrode active material and its precursor are provided at low cost. Moreover, the said precursor for lithium ion secondary battery positive electrodes is obtained by the manufacturing method of this invention. They are useful in the field of lithium ion secondary batteries, and their applicability in this field is extremely high.

The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2010-179712 filed on August 10, 2010 are cited herein as disclosure of the specification of the present invention. Incorporated.

Claims (15)

1. Nickel-M element containing nickel ammine complex and M element source (wherein M element is at least one selected from the group consisting of transition metal elements excluding Ni and Co, alkaline earth metal elements and aluminum) Step 1 of obtaining a suspension slurry containing particles of the nickel-M element-containing composite compound by decomposing the nickel ammine complex by heating the solution or dispersion, and drying and granulating the suspension slurry, A method for producing a nickel-M element-containing composite compound for a secondary battery positive electrode active material, comprising the step 2 of obtaining a granulated product of an element-containing composite compound.
2. In nickel -M element-containing complex compound, Ni, the ratio of Co and M _element, when the Ni a _Co b _{M c,} in atomic ratio, 1 ≦ a ≦ 0.85,0 ≦ b ≦ 0.85,0 The method for producing a nickel-M element-containing composite compound according to claim 1, wherein 0.03≤c≤0.8 and a + b + c = 1).
3. The method for producing a nickel-M element-containing composite compound according to claim 1 or 2, wherein the nickel-M element-containing composite compound is a compound containing at least one selected from the group consisting of a hydroxyl group, a carbonate group, and an OOH group.
4. The nickel-M element-containing composite compound according to any one of claims 1 to 3, wherein the step 1 heats the nickel-M element-containing solution or dispersion at 80 to 250 ° C under a pressure of 0.03 to 2 MPa. Production method.
5. 4. The nickel-based nickel alloy according to claim 1, wherein said step 1 heats the nickel-M element-containing solution or dispersion by introducing steam at 100 to 250 ° C. under a pressure of 0.03 to 2 MPa. Manufacturing method of M element containing complex compound.
6. 6. The method for producing a nickel-M element-containing composite compound according to claim 1, wherein the nickel ammine complex is a carbonate ammine complex.
7. The method for producing a nickel-M element-containing composite compound according to any one of claims 1 to 6, wherein the M element source contains manganese and the manganese source is a manganese ammine complex.
8. The method for producing a nickel-M element-containing composite compound according to claim 7, wherein the manganese ammine complex is manganese carbamate.
9. The method for producing a nickel-M element-containing composite compound according to any one of claims 1 to 8, wherein the dry granulation in step 2 is performed by spray-drying a nickel-M element-containing solution or dispersion.
10. 10. The method for producing a nickel-M element-containing composite compound according to claim 1, wherein the suspension slurry has a solid content concentration of 10% by mass or more and a viscosity of 2 to 1000 mPa · s.
11. 11. The method for producing a nickel-M element-containing composite compound according to claim 1, wherein the average particle diameter D ₅₀ is 6 to 30 μm.
12. The method for producing a nickel-M element-containing composite compound according to any one of claims 1 to 11, wherein the sodium content is 0.01 mass% or less.
13. The method for producing a nickel-M element-containing composite compound according to any one of claims 1 to 12, wherein the sulfur content is 0.1 mass% or less.
14. A nickel-M element-containing composite compound obtained by the production method according to any one of claims 1 to 13 and a lithium compound are mixed, and then fired at 700 to 1100 ° C in an oxygen-containing atmosphere. A method for producing a composite oxide.
15. A method for producing a lithium ion secondary battery comprising a positive electrode active material for a lithium ion secondary battery comprising a positive electrode, a negative electrode, a non-aqueous electrolyte and an electrolytic solution, wherein the positive electrode is obtained by the production method according to claim 14.

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